Shell for high explosives



N No. 622,479. Patented Apr. 4, I899.

r W. S. ISHAM.

SHELL FOR HIGH E XPLOSIVES.

' (Application filed Nov. 29, 1898.)

(No Model.)

2 Sheath-Sheet I.

Patented Apr. 4, I899.

w. s. ISHAM. SHELL FOR HIGH EXPLOSIVES..'

(Appiication filed Nov, 28, 1898.)

2 Shaats 8heet 2.

(No Model.)

Nrrnn STATES IVILLARD S. ISHAM, OF WVASI-IINGTON, DISTRICT OF COLUMBIA,ASSIGNOR,

BY MESNE ASSIGNMENTS, OF ONE-HALF TO DELMAR W. SMITH, OF MID- DLEBURY,VERMONT.

SHELL FOR HIGH EXPLOSIVES.

SPECIFICATION forming part of Letters Patent No. 622,479, dated April 4,1899. Application filed November 8,1 898. Serial No. 697,573. (Nomodel.)

To all whom it may-concern: equals maximum pressure in pounds per Be itknown that I, WILLARD S. ISHAM, a square inch of firing charge, A equalsarea of citizen of the United States, residing at WVashbase of shell, 10equals weight in pounds per ington, in the District of Columbia, haveincubic inch of high explosive, W equals total vented certain new anduseful Improvements Weight in pounds of shell loaded, and h equals 55 inShells for High Explosives; andldoheremaximum height of any charge ininches. by declare the following to be a full, clear, and Now thispressure p on the bursting charge exact description of theinvention,such as will must be less than the minimum pressure per enable othersskilled in the art to which it apsquare inch necessary to detonate thehigh 10 pertains to make and use the same. explosive -that is, 1J D,when D equals pres- 6 My invention relates to improvements in sure inpounds per square inchnecessary to shells, and in particular toarmor-piercing detonate the said high explosive. Substitutprojectilesintended to carry a charge of high ing, We have explosives. I The objectof my invention is to provide a m D.

shell which will enable a charge of high ex- W plosives to be fired froman ordinary gun in All the factors involved in my formula are the usualmanner of firing shells Without dan-, n known t, hmth i h i ht f of apremature explosionthe charge of high explosive. This can be 2 AnotherObject of ihVehlilOh is to P deduced readily bymeans of the formula. 70vide a shell for carrying a high explosive It is to be understood thath, the height of Which Will be able to pierce armor, the piercthebursting charge, is the maximum height lllg' Of the armor taking placeprior to the BX- f such charge in any one compartment or plosieh 0f theShell chamber measured in the direction of the lon- M y attempts hfiWebeen made hitherto t0 gitudinal axis of the shell. Furthermore, the 7 5construct shells by means of which high exproduct P A is the totalmaximum pressure plosives could be fired from an ordinary gun f th fi icharge on the b e f th 1 11, In the usual Way Of firing SllOl] andshell. All and w, the weight, per ubic inch of the high such attemptshave been f explosive, may for brevity be called the den- 3o 1 havediscovered the law relat ve to the sity of such high explosive. 8opressure on the bursting charge of high explo- My invention, broadlyconsidered, consists sives due to the pressure of the firing charge, ina projectile provided With chambers arand as a result of such discoverylam enabled ranged to carry charges of high explosives, to constructshells O g P OS G 0f a y none of which chambers are to receiveacharge 35 kind. of such high explosive having a height greater 85 According tothe law discovered by me the than is imposed by the formula maximumpressure on the bursting charge due to the inertia of said charge isdirectly proportional to the maximum pressure per square WV inc 9 lBhe gCharge, the a of the It is especially important in the construe 9 e qbase of e Shell, to P Welghl? P tion of a shell for high explosives thatthe ellhle lheh 0f the hlgh jp e v aha e chambers have their Wallswithout joints and h 0f the charge e 13 hwelsely P PQ that the chambersbe absolutely isolated from hlehal to the hotel Welghh of the Shell, 1each other. Furthermorefior an armor-pierchPAw D.

algebraic language, ing projectile the'construction should be such 5 P AU that the pressure due to impact shall not be 1 transmitted to the chares. These further requirements are met by the preferred form when equalsmaximum pressure in pounds of my invention, which therefore consists,furper square inch on the high explosive, P ther, in a shell embodyingthe features, de

tails of construction,and combination of parts, which will first bedescribed in conection with the accompanying drawings and then particularly pointed out in the claims.

' In the drawings, Figure l is a longitudinal central section of a shellembodying my invention in its preferred form; Fig. 2, a transversesection of the same on the line 2 2, Fig.

1; Fig. 3, a similar view on the line 3 3, Fig.

1, showing a portion of the wall of the shell with a charging-hole andits plug; Fig. 4, a diagrammatic view illustrating the construction ofthe point. Figs. 5, 6, and 7 are diagrammatic views illustrating thechanges that would be made in the heights of the chambers in accordancewith my invention where the propelling charge is varied in size, itbeing assumed, for the sake of this illustration, that the pressureproduced by the firing charge will always be proportional to the size ofsuch firing charge. Figs. 8, 9, andlO are similar views illustrating thechanges that will be made in the heights of the chambers in accordancewith my invention where the weight of the shell is varied, the otherfactors remaining constant, as will be more fully explained hereinafter.

Referring to thedrawings, A is the wall of the shell; B, the nose orpoint; C, a pillar or column; D, a base, and E a plurality of transversepartitions, these parts all being made integral with each other in anysuitable manner, so that the chambers have no communication with eachother. The spaces between the partitions form charge-chambers F,arranged to receive charges which are proportioned in accordance with myformula.

It is absolutely necessary that none of the charges exceeds the limitsin height imposed by my formula, and it is preferable that the chambersbe also so proportioned that each charge will just fit its chamber.

Through the pillar or column 0 extends a main vent c, which crosses andcommunicates with a plurality of transverse chamber-vents 0, openinginto the respective chambers F. Each chamber F is provided with acharginghole a, formed in the wall A of the shell, each charging-holebeing opposite the chambervent c of its respective chamber and beingconical in form, as shown on an enlarged scalein Fig. 3. Thecharging-holes are screwthreaded and into each is screwed a plug a,which is correspondingly cone-shaped, as shown in said Fig. 3.

The base D of the shell contains a recess d, arranged to receive a fuseof any desired or .usual construction, which fuses being well known tothose skilled in the art need not be specifically described herein.

After the shell has been cast and before the vents are formed thechambers may be tested.

the chamber-vents are drilled by inserting a drill through thecharge-holes.

-A small stopper or plug is inserted into the chamber-vent beforeloading the chamber, as shown at X, Fig. 1. These plugs are usually, butnot necessarily, of soft wood and are intended to be blown into thechambers upon the detonation of the fuse. The plugs for the charge-holesmay then be screwed into place and the fuse secured in the recess at thebase, thus completing the shell. In Figs. 1 and 3 the charge is shown atG.

A shell embodying all the specific features of myinvention has acentrally-arranged column or pillar 0, whose diameter is greater thanthe thickness of the wall A of the shell and whose cross-sectional areais less than the cross-sectional area of saidwall A, the columnextending entirely from the point B to the base D. The point of theshell is substantially conical or conoidal, the base of the cone orconoid being practically concentric with the forward end of the columnor pillar 0. Furthermore, the said point is so proportioned that thesides of an imaginaryinverted frustum of a cone resting on the front endof the pillar and having its sides at an angle of fortyfive degrees willintersect the surface of the nose or point A in a circumference lyingdirectly ahead of the wall of the shell. By this construction the columnor pillarwill sustain the whole impact of the shell when first strikingan armor-plate and up to the time that the cross-sectional area of thatportion of the nose lying in the plane of the armor-surface is notgreater than the cross-sectional area of the column or pillar. As thepoint penetrates deeper into the armor the pressure will be'distributedbetween the column and the wall of the shell, the major component,however, being transmitted to the column until the nose has penetratedto such a depth that the points of intersection of the sides of saidimaginary frustum and the outer surface of the shell will be beyond theplane of the outer surface of the armor, whereupon the major componentof the pressure falls upon the walls of the shell. Since the strain istransmitted longitudinally to the shell-wall, it is readily resisted bythe same, this being possible with a comparatively thin wall, owing tothe fact that its cross-section is not weakened by joints and alsobecause the partitions are integral with said wall, and thereby preventbulging of the same. Moreover, the partitions brace the column in thesame manner, thereby rendering it possible to make the latter of asmaller diameter than would otherwise be the case, the result being thata shell made in accordance with my construction will have a largercapacity for a bursting charge.

It will be plain that by the particular formation of the point or nosewhich I have described above the pressure due to impact will betransmitted at first entirely to the column,

then partly to the column and shell, and

I nose.

finally to the shell and that this pressure will be at all times in thedirection of the lengths of the said column and wall and at no time willthere be any pressure from impact on the charge in-the shell, exceptsuch as due to the momentum of the charge, which, being no greater thanthe inertia at the time of firing, (if the shell penetrates the armor orother obstruction,) will not cause an explosion of the said charge,wherebyit becomes possible for the shell to pierce and pass through anobstruction before exploding, the time of explosion being controlledwholly by the fuse. It will be apparent, therefore, that the pillar isarranged to afford a continuous solid support for the initialpenetrating portion of the Moreover, the momentum of the pillar actsdirectly on the nose and assists in driving the same through theobstruction, such asarmor.

\Vith reference to so much of my invention as concerns theproportionalsize of the chambers or of the charges, if the chambers are not to beentirely filled, it is to be understood that a shell embodying suchfeatures is intended for charging with explosives which may be detonatedby'pressure. This is the sense in which the term high explosives isgenerally used and is the meaning which I attach to said term in thisspecification. Hence attention is directed to the fact that my formulacontains as a factor D the pressure per square inch necessary todetonate the explosive charge. This is important, because this pressurevaries with different high explosives, and consequently a shell whichwould have chambers suitably proportioned according to my formula forone kind of highexplosive charge might be inoperative for .use withanother kind of high explosive. be understood, of course, that D is wellknown for all high explosives.

In Figs. 5, 6, and 7 I have shown how the heights of the chambersproportioned in accordance with my invention will vary as the firingcharge varies. It will be noted that the firing charges increase in sizefrom Fi 5 to Fig. 7 being smallest in the former view and largest in thelatter view. It will also be noted that the heights of the chambers ofthe shells decrease from Fig. 5 toFig. 7, being greatest in Fig. 5 andleast in Fig. 7. In these three views it is assumed that the weight anddiameter of the shell, the kind and quality of the high-explosivebursting charge, and the kind and quality of the firing charge remainunchanged. Furthermore, it is also assumed that the maximum pressure ofthe firing charge is proportional to the size of said firing charge. Ofcourse it is to be understood that a difference in quality of powderwill also cause a diiference in the maximum pressure generated by suchfiring charge.

In Figs. 8, 9, and is illustrated the manner in which the heights of thechambers will vary with the variation in the weight of the shell, suchheight being least in Fig. 8, where It will the weight of the shell isleast, and greatest in Fig. 10, where the weight is greatest. In theseviews it is assumed that the kind, quality, and quantity of the firingcharge and the kind and quality of the high-explosive burstingcharge'are unchanged.

As will be seen from the drawings, the difference in weight of the shellmay be caused by a difference in the length of said shell, asillustrated by Figs. 8 and 9, or by a difference in thickness of wallsor columns, as will be clear from a comparison of Figs. 9 and 10.

\Vhile the said views Figs. 5 to 10 are made to a scale illustrating aseven-inch shell, they are only intended as illustrative examples'tomake clear in a general way the gist of my invention, and it is to beunderstood that my invention is not restricted to the proportionstherein shown nor to those changes only, the full scope of my inventionbeing pointed out in the claims.

\Vhile I have particularly mentioned the use of the shell for piercingarmor, it is to be understood that it may be used for piercing anyobstruction or resistance-such as masonry, earthworks, and the likeandthe term .armor is used by me in this generic sense.

For firing dynamite or other high explosives in which nitroglycerin is acomponent it is highly important that the shell shall be formed integralinstead of being built up of parts screwed or otherwise fastenedtogether in a detachable manner for the following reasons: When theshell is made of such parts, the joints, no matter how well fitted, arenot absolutely closed at all points, for. even though water-tight therewill be marginal edges which do not contact throughout. As thenitroglycerin will exude to a slight extent from the explosive charge,it will enter such joints, although of course only to an almostinfinitesimal extent. Yet even such a small amount will cause thepremature explosion of the shell, since at the moment of firing thejoints are compressed with great force, and consequently thenitroglycerin caught therein is exploded, this in turn detonating theremaining charges of the shell.

In my construction no attention is paid to the inertia of rotation ofthe bursting charge, because the shell can rotate while the burstingcharge is relatively stationary at the start, and there is no lateralsurface for such bursting charge to press against. Thus all danger ofexplosion from rotation is avoided. Eventually, of course, the chargeacquires a certain amount of rotary motion through friction.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent of the United States, is

1. A shell for high explosives having chambers provided with burstingcharges, none of said bursting charges having a maximum height equal tothat obtained by dividing the product of the total weight of the shell,loaded, and the minimum pressure per square inch necessary to detonatethe high explosive, by the product of the maximum total pressureof thefiring charge on the base of the shell and the density of the highexplosive.

2. Ashell for high explosives having chambers provided with burstingcharges, none of said chambers having a maximum height equal to thatobtained by dividing the product of the total weight of the shell,loaded, and the minimum pressure per square inch necessary to detonatethe high explosive, by the product of the maximum total pressure of thefiring charge on the base of the shell and the density of the highexplosive.

3. A shell for high explosives having a plurality of non communicating,entirely inclosed chambers provided with bursting charges, none of saidbursting charges having a maximum height equal to that obtained bydividing the product of the total weight of the shell loaded and theminimum pressure per square inch necessary to detonate the highexplosive, by the product of the maximum total pressure of the firingcharge on the base of the shell and the density of the high explosive.

4. An integral shell for high explosives having a plu rality ofnon-communicating entirely inclosed chambers provided with burstingcharges, none of said bursting charges having a maximum height equal tothat obtained by dividing the product of the total weight of the shellloaded and the minimum pressure per square inch necessary to detonatethe high explosive, by the product of the maximum total pressure of thefiring charge on the base of the shell and the density of the highexplosive.

5. A shell forhigh explosives havinga shellwall, a centrally-arrangedpillar Within the same and integral therewith and annular compartmentsaround the pillar.

6. A shell forhigh explosives having a shellwall, a centrally-arrangedpillar within the same, and a nose integral with the wall and pillar,the diameter of the pillar being greater than the thickness of the wall.

' '7. Ashellforhigh explosiveshavingashellwall, a centrally-arrangedpillar Within the same and a plurality of transverse partitionsextending from the pillar to the Walls and integral with the pillar andwalls.

8. A shell for high explosives having a shell- Wall, acentrally-arranged pillar and a nose Whose base'is concentric with thefront end of the pillar, said parts being integral, the proportions ofthe point, being such that an imaginary inverted frustum of a coneresting on the front end of the pillar and having its sides sloping atan angle. of forty-five degrees would intercept the outer surface of thepoint in a circumference lying directly forward of the wall of theshell, substantially as described.

9. Ashellforhighexplosiveshavingashell- Wall, a central pillar, a noseand transverse partitions extending from the pillar to the Wall, thepillar having a longitudinally-arranged main vent and chamber-ventsopening into said main vent and into the chambers formed between thepartitions, in combination with a fuse at one end of the main vent,substantially as described.

10. A shell for,high explosives having a shell-wall, a central pillar, anose and transverse partitions extending from the pillar to the wall,all the parts being integral, the pillar having alongitudinally-arranged vent and chamber-vents opening into said mainvent and into the chambers formed between the partitions,the Wall beingprovided with chargin g-holes, one for each chamber, each hole bein gopposite its corresponding chamber-vent.

In testimony whereof I affix my signature in presence of two witnesses.

WILLARD S. ISHAM.

Witnesses:

M. O. MAssIn, ANTON A. GLOETZNER.

